AppleScript

So, as I wrote in the comments, you can do this with AppleScript. Here I show how to create a service that types your clipboard using 'keystrokes'.

First create an automator 'Service' project and add a 'Run AppleScript' module. Enter the following script.

set clipboardText to (the clipboard as text)
set theCharacters to characters of clipboardText
repeat with char in theCharacters
    tell application "System Events"
        keystroke char
    end tell
end repeat

return input

Now you can find this 'Service' in your 'Service' menu.

You can also create a keyboard shortcut (for example ctrlshiftv) in your System Preferences [Keyboard -> Shortcuts -> Services]. Now you can 'type' your clipboard anywhere when pressing ctrlshift.

If you look at the details of a homebrew package (e.g. on http://braumeister.org), you'll find the address of the source code in the ruby script. So it is not stored in a centralized manner but directly on GitHub etc.

Anyone can submit a package to be installed and the maintainers either accept / modify / reject hosting the software in the main directory.

However, it’s easy to set up your own directory and tap that and then install anything you want using the homebrew scripts and tools. It’s pretty open to change if you want to add to it.